442 ROSACEAE 



R. acicularis X nutkana. This hybrid has the bristly stems, the elongate hypan- 

 thium, and the narrow, elliptic leaflets of R. acicularis, but the bristles are stronger, 

 some of them stout and nearly 1 cm. long, the leaflets are often double-toothed and much 

 less hairy beneath than in R. acicularis. Mont. 



8. R. Bourgeauiana Crep. Stem usually low, 3-10 dm. high, densely 

 covered with straight bristles or weak prickles; stipules slightly, if at all, pubes- 

 cent, glandular-dentate; petiole and rachis somewhat pubescent and glandular; 

 leaflets usually 5 or 7, broadly elliptic, 1.5-5 cm. long, usually rounded or obtuse 

 at both ends, more or less double-serrate, thin, glabrous or nearly so above, 

 slightly pubescent and gland ular-granuliferous beneath; hypanthium glabrous, 

 in fruit 12-15 mm. broad; sepals slightly, if at all, glandular; petals broadly 

 obcordate, 2-2.5 cm. long, rose-colored. R. Sayi S. Wats., not Schwein. Woods: 

 Ont. Colo. Mont. Mack. Boreal Submont. Mont. Je-Jl. 



R. Bourgeauiana X nutkana. This resembles R. Bourgeauiana in the numerous 

 bristles or rather weak prickles, but the prickles are stronger than in that species and 

 many of them have broadened bases ; the leaves are also firmer and conspicuously double- 

 toothed as in R. nutkana. Mont. 



9. R. MacDougali Holz. Stem erect, 1-2 m. high, usually armed with 

 paired straight, rather stout infrastipular prickles, 7-10 mm. long; floral branches 

 with weaker prickles or unarmed; stipules puberulent and somewhat glandular 

 beneath, glandular-dentate; petiole and rachis puberulent and slightly glandular; 

 leaflets usually 7, oval, 1.5-5 cm. long, coarsely and rather regularly toothed, 

 glabrous or nearly so above, puberulent beneath; pedicels more or less glandular- 

 bristly; hypanthium subglobose, densely bristly or prickly, without a neck, in 

 fruit 12-18 mm. broad; sepals glandular on the back; petals broadly obcordate, 

 2-3 cm. long, rose-colored. R. nutkana hispida Fern. Woods: Ida. w Mont. 

 n Utah Wash. B.C. Submont. My-Je. 



10. R. nutkana Presl. Stems stout, erect, usually 1-1.5 m. high, armed 

 usually with paired large straight prickles, which are somewhat flattened below, 

 6^-12 mm. long; floral branches glabrous, with smaller infrastipular prickles; 

 stipules mostly glabrous, strongly glandular-dentate on the margins; petiole and 

 rachis glandular-puberulent; leaflets 5-9, usually 7, rounded-ovate, rounded at 

 the both ends or acute at the apex, double-serrate, with glandular teeth, 1.5-5 

 cm. long; hypanthium glabrous; sepals glabrous or rarely glandular on the back; 

 petals rose-colored, rarely white, broadly obcordate, 2-3.5 cm. long. Woods: 

 Alaska w Mont. Wyo. n Calif. Submont. Mont. My-Jl. 



11. R. muriculata Greene. Stem stout, erect, 1 m. high or more, armed 

 with paired infrastipular prickles, which are straight, stout, slightly ascending, 

 8-10 mm. long, flattened below; floral branches unarmed or with weak prickles; 

 stipules densely glandular-muricate ; petioles and rachis strongly glandular and 

 more or less prickly; leaflets 5 or 7, broadly oval or subrotund, rounded at the 

 apex, glandular double-toothed, dark green on both sides, 1.5-3 cm. (rarely 4 

 cm.) long; hypanthium subglobose, glabrous, in fruit 12-15 mm. in diameter; 

 sepals glandular-hispid on the back; petals obcordate, 2-2.5 cm. long. Woods: 

 B.C. Mont. Ore. Submont. 



12. R. Spaldingii Crep. Stem erect, about 1 m. high, usually armed with 

 straight paired prickles, 5-10 mm. long; floral branches glabrous, somewhat 

 prickly; stipules finely puberulent and somewhat glandular-toothed; petiole and 

 rachis grayish-puberulent and sometimes slightly glandular; leaflets 5-7, oval 

 or rounded, coarsely and usually regularly toothed, 1.5-5 cm. long, pale and 

 puberulent beneath; hypanthium glabrous; sepals glabrous or very rarely glandu- 

 lar on the back; petals rose-colored, 2-3 cm. long; hypanthium in fruit globose, 

 without neck, 12-18 mm. thick. Woods: B.C. Wyo. Utah Ore. My-Jl. 



13. R. Underwoodii Rydb. Stem 1-2 m. high, glabrous, armed with 

 stout, recurved, paired infrastipular prickles (and also often with scattered ones) 

 5-10 mm. long; stipules puberulent, glandular-dentate; petiole and rachis puberu- 

 lent and with sessile glands; leaflets 5-7, obovate or oval, 2-4 cm. long, some- 

 what irregularly or doubly serrate, glabrous on both sides or finely puberulent 

 and paler beneath; hypanthium more or less pear-shaped, sparingly bristly, in 

 fruit about 2-3 cm. long and 1.5-2 cm. broad; sepals glandular and pubescent on 



